It will pass. The SNP, Tories and Labour all supported it. The bill to introduce the APD rate passed by a considerable majority (108 for, 11 against, SNP only have 63 MSPs) with the Tories pretty much fully behind any kind of change. There just needs to be some agreement on how to go forward but a change will be approved, for sure. The greens don't support everything the SNP want, barely anything in fact, they are only aligned on independence, they disagree on many things.
http://www.bbc.co.uk/news/uk-scotlan...itics-40332210
As for the English airports, BHX, MAN, NCL were all actively pushing for a block on the APD devolution. Instead of focusing their energy on central government to start with.
Newcastle Airport chief lobbies party leaders over crucial Air Passenger Duty - The Journal
English airports cry foul over Scottish air tax competition (From HeraldScotland)
I think it's a bit rich for the combined effort, especially when BHX and MAN already do extremely well for long haul services with the current APD rate and Scottish reductions will pose no threat to them whatsoever. NCL is the only airport which really has a case, but that itself is no reason to prevent Scotland from attracting more business.